THE IMPORTANCE OF MATERIAL STRUCTURE IN THE LASER CUTTING OF GLASS-FIBER-REINFORCED PLASTIC COMPOSITES

A previously proposed micromechanical formula, aiming to predict the v aporization energy Q(v) of composite materials as a function of fiber and matrix properties and fiber volume ratio, was assessed. The experi mental data, obtained on glass fiber reinforced plastic panels with di fferent fiber contents cut by a medium power CO2 cw laser, were treate d according to a procedure previously suggested, in order to evaluate Q(v). An excellent agreement was found between experimental and theore tical Q(v) values. Theory was then used to predict the response to las er cutting of a composite material with a fiber content varying along the thickness. The theoretical predictions indicated that, in this cas e, the interpretation of the experimental results may be misleading, b ringing to errors in the evaluation of the material thermal properties , or in the prediction of the kerf depth. Some experimental data were obtained, confirming the theoretical findings.